The invention relates to apparatus for idle speed control of internal combustion engines and more particularly to an adjustable throttle valve closure sensing switch incorporated in apparatus for adjusting throttle valve position to control idle speed
United States patent application 108,497 filed Dec. 31, 1979, now abandoned and assigned the same assignee as the present application, discloses apparatus for adjusting the position of a throttle valve on a carburetor to control engine idle speed. One phase of operation of such apparatus is sensing throttle valve closure and supplying an indication thereof to an electronic unit which, in turn, determines the degree of throttle valve closure necessary to have the engine operate at some predetermined idle speed and commands the apparatus to limit the degree of closure so that idle speed is maintained. For this purpose, a switch is incorporated in the apparatus described in the application to detect when the throttle valve is closing and to provide an electrical indication of such closure to the electronics unit.
The present application describes an improved switch mechanism for sensing throttle valve closure. The mechanism described herein is advantageous in that it includes a preloading feature for compensating for limit stack tolerances which result during fabrication of apparatus such as that described in the aforementioned application, as well as an adjustability feature for facilitating calibration of the apparatus.